conceived by wildcatter Glenn McCarthy as a city-sized hotel scaled for conventions with a resort atmosphere. The Shamrock was located in a suburban area three miles (5 km) southwest of downtown Houston on the fringes of countryside and was meant to be the first phase of a much larger indoor shopping and entertainment complex called McCarthy Center, anchored alongside the planned Texas Medical Center. At the hotel's north side was a five-story building containing a 1,000-car garage and exhibition hall. To the south was the hotel's lavishly landscaped garden designed by Ralph Ellis Gunn, a terrace and an immense swimming pool measuring 165 by described as the world's biggest outdoor pool, which accommodated exhibition waterskiing and featured a three-story-high diving platform with an open spiral staircase. Despite protests by local preservationists, the Shamrock was demolished June 1, 1987. The Institute of Biosciences and Technology now stands in its former location. The 18-story Prudential Building, designed by Kenneth Franzheim, was constructed in 1952 in the Texas Medical Center. The ground level walls of the Prudential Building were clad with deep red polished Texas granite; the upper floors on the northwest and northeast sides were clad in Texas limestone. The southwest and southeast sides, though, were faced with full-height aluminum arrangements to "utilize solar rays and air circulation to effect economies in air conditioning." The building was the first local corporate high rise office building in Houston to be located outside of the central business district. The Prudential Building was demolished January 8, 2012. In the 1960s, Downtown Houston was a modest collection of mid-rise office structures, but has since grown into the third largest skyline in the United States. In 1960, the central business district had 10 million square feet (1,000,000 m²) of office space, increasing to about 16 million square feet (1,600,000 m²) in 1970. Downtown Houston was on the threshold of a boom in 1970 with 8.7 million square feet (870,000 m²) of office space planned or under construction and huge projects being launched by real estate developers. The largest proposed development was Houston Center, originally planned to encompass a 32-block area. However, by 1989, when the company that acquired the original developer sold Houston Center, the complex consisted of three office buildings, a shopping center, and a hotel. Other large projects included the Cullen Center, Allen Center, and towers for Shell Oil Company. The surge of skyscrapers mirrored